M103 - Upper Timing Chain Cover and Cam Seal Leaks
 

When resealing the upper timing chain cover on a M103, what's the preferred way to renew the camshaft seal? Install the timing cover and then insert a new cam seal or.... install the cover with the new cam seal already in place?

I vote for your first suggestion and here are a couple of special tools that may aid in this. Check out part numbers M0003 and M0004. Depends on what yr. your engine is.

http://www.autospecialtytools.com/cgi-bin/dyn.exe?doc=sirtools9.dht&

I've done it both ways. The first time after installing a rebuilt head after a timing chain failure. The seal leaked, but since the cover was not leaking, I didn't want to redo the cover.

I dug out the seal, cleaned the surface of the cover and inserted another seal. (oiled on the inside) I tapped it into place using a tack hammer until the seal was evan with the surface of the cover. No leak now.

Cam Seal Replacement
 

I just resealed the upper timing cover and replaced the cam seal on my '88 260E. I installed the seal in the cover first, but it was difficult lining up the cam seal and the timing cover on the studs and it is easy to damage the seal while installing the cover.

Mine turned out okay and the timing cover is as dry as a bone but if I had to do it again, I would install the seal after the cover is in place. Use a block of wood to drive it flush with the face of the timing cover. I also used some 600 grit sandpaper to smooth the end of the camshaft so it wouldn't cut the new seal (it was very sharp).

Question. With the cam seal leaking, couldn't this wet the inside of the cap and the rotor causing the car to run *****ty? And also, cause a poor idle?
The reason that I'm asking this is I just changed my cap and rotor and noticed that the drivers side of the seal was sticking out. i have no idea why but I'm changing it now..

I'm guessing not, unless it was spraying out. Which it won't be. It'll just drip down and run down the front of the cover.

Thank you

It is no big deal to replace this seal by removing the upper cover if you know the key. Get the recommended sealer from MB. It will let you slide the cover rearward without disturbing the lower U Seal gasket. Put the seal in the cover on the bench, then oil the seal. While sliding the cover rearward use your fingernail to see that the seal is starting over the shaft smoothly. Push the cover rearward into place and bolt in place.

Gob the sealer in the lower rear corners, and of course, use it on the U Seal and rear sealing surface.

Nothing to it if you're using the right stuff.

Good luck,

MB Sealant
 

I agree with the MB Sealant statement, made by loctite I could not find anywhere locally, ordered through this site. My car is dry of oil for first time since I bought it a year and half ago.

Would only use this stuff, not worth pulling apart to fix again if I used the wrong stuff.

Joel

a question
 

part number for this stuff? the manual seems to indicate one type of sealant for the corners and another part number for the metal to metal seal? Your suggestions is to place the sealer on all contact surfaces. so put the sealer on top of the rubber "U" gasket as well as in the corners and on the metal mating surfaces? I am reinstalling the top cover this weekend and want to get it right.:)

Its not cheap, but it does work... 001 989 89 20-10

It's not cheap is right. I checked at Smythe European in San Jose, CA and it's $56 plus tax.

Sixto
91 300SE
87 300SDL
83 300SD

Just reviewed service task 01-212 - removing installing top front cover off the 126 CD-Rom - 103 motor in my 126.

Two(2) different sealers are mentioned.

001 989 61 20 10 - seals the u-gasket in the corners

002 989 00 20 10 - used to coat contact surfaces of front cover to cyl. head

Looked at this sites PartsShop and found 5 different sealers that start with 001 989 as does the u-gasket sealer mentioned above. They range in price from $9.50 - $21.00. Did not find an exact match for the sealer # mentioned above.

Also found one that's close to the 002 989 mentioned above - it sells for $17.14

I realize that numbers get superceded, but for the moment, I'm confused as hell.

Yep, use only the MB sealant and all works out OK.

(1) is a pink-color anerobic sealant (seals in the absence of air);
(2) is a gray-color aerobic sealant that will harden in the presence of air.

:-) neil

Neil,

Did you catch the C43 engine for sale in the parts forum?

http://www.peachparts.com/shopforum/showthread.php?threadid=54034

Might help the TE keep up with the E500 :)

Sixto
91 300SE
87 300SDL
83 300SD

The best procedure I found for the "u" seal is to use a dab of sealant at the ends where it butts against the cover, but use no sealant anywhere else on it. instead just "spit" on it, then place it in the groove, and slide the upper cover on. The spit is the slickest thing known to man, and allows the seal to retain perfect form and position as the upper cover easily slides over it. When the spit dries it causes good adherance of the seal to the cover with no globs of sealant, no drying of sealant later, etc. Works great! You've all probably used spit on 0-rings - same deal.

S-Class Guru

You can buy German spit at the dealer. Comes is a little plastic bottle about the size of fingernail polish for about $20. It is not cheap either, but it is better to use a high quality spit and do it right the first time, rather than having to repeat the job later.

Call Phil
 

Mike,

Call phil, tell him the application and he'll hook you up with the correct sealant.

Good luck,
Joel

The rubber compound in the u-seal was developed for German spit. If you have less than 1/4 German in your ancestry, you must purchase the German spit from the MB dealer.

The only alternative is for all your favorite curse words that you use during this repair be German curse words. I know plenty of them, but will not repeat them here.

Good luck,